Tufting machine hook and knife mechanism



Dec. 21, 1965 I H. WITTLER 3,224,396

TUFTING MACHINE HOOK AND KNIFE MECHANISM Filed Dec. 9, 1963 INVENTOR. i2 BY Bernard H.W|Hler Witness Z wa/b M M Attorney United States Patent3,224,396 TUFTING MACHINE HOOK AND KNIFE MECHANISM Bernard H. Wittler,Rossville, Ga., assignor to The Singer Company, New York, N.'Y., acorporation of New Jersey Filed Dec. 9, 1963, Ser. No. 329,061 3 Claims.(Cl. 112-79) This invention relates to a cut pile tufting machine andhas as its primary object to provide a cut pile tufting machine capableof high speed operation.

In a cut pile tufting machine, there is provided an oscillatable hookincluding a loop-seizing blade having a cutting edge along its loweredge and an oscillatable knife blade having one surface in abutment withone surface of the hook and having a cutting edge along its upper edgethat cooperates in a scissor-like manner with the cutting edge of thehook to cut a loop of yarn on the loop-seizing blade of the hook.

During operation of the machine, friction between the hook and the knifeblade generates a considerable amount of heat which limits the operatingspeed of the machine. When it is attempted to operate the machine at aspeed in the neighborhood of 3,000 stitches per minute, the heat that isgenerated is so intense that the knife blade is destroyed within a fewminutes' Besides initially destroying the temper of the metal, the heatcauses the knife blade to burn through the loops of yarn instead ofcutting them; and when synthetic yarn is used, the cut pile fusestogether. Oil, and all similar lubricants, cannot be used because of theintimate association of the hook and the knife blade with the pile yarn.

It is, therefore, another object of the invention to provide an improvedmeans for reducing the heat generated between the opposed surfaces of ahook and a knife blade in a cut pile tufting machine.

Another object of the invention is to provide a means in accordance withthe foregoing object for lubricating the opposed surfaces of a hook anda knife blade in a cut pile tufting machine Without soiling the pileyarn.

A still further object of the invention is to provide an improved meansfor biasing a knife blade against one face of a hook in a cut piletufting machine.

Other objects and a fuller understanding of the invention may be had byreferring to the following description and claims, taken in conjunctionwith the accompanying drawings in which:

FIG. 1 is a side elevation of the device of the invention,

FIG. 2 is an exploded perspective view of the hook and the knife bladeshown in FIG. 1,

FIG. 3 is a section view taken along the line 3-3 in FIG. 1, and

FIG. 4 is a top plan view of the device of the invention.

With reference to the drawings, there is provided a hook mechanism and aknife mechanism 11. The hook mechanism 10 includes a hook bracket 12connected to an oscillatable hook shaft 13 by means of a screw 14.Carried by the bracket 12 is a hook bar 15 having a hook receiving slot16.

A hook 17 having a mounting portion 18 at its lower end is removablysecured in the slot 16 in the hook bar 15 by means of a setscrew 19. Thehook 17 has a loopseizing blade 20 at its upper end, and a cutting edge21 is formed along the lower edge of the loop-seizing blade 20.

A block 22 having a bore 23 therethrough is secured to one surface ofthe hook 17. One end of the bore 23 in the block 22 is in communicationwith a bore 24 in the hook 17 having an opening 25 on the surface of the3,224,395 Patented Dec. 21, 1965 added substance for the bore 23.

The knife mechanism 11 of the machine includes a knife bracket 27connected by means of a screw 28 to an oscillatable knife shaft 29 thatis parallel to the hook shaft 13. Lever means including a knife carrier30 is pivotally secured to the top of the knife bracket 27 by means ofits shaft 31 held by a bushing plate 32 and screws 33.

The knife carrier 30 has an arm 34 connected to the top of the shaft 31with an aperture 35 in its free end. A knife blade 36 having a lug 37projecting from one surface is removably connected to the free end ofthe arm 34 of the knife carrier 30 by means of a snug fit between thelug 37 and the complemental aperture 35 formed in the free end of thearm 34. A cutting edge 38 is formed along the upper edge of the knifeblade 36. It is within the scope of the invention to have the opening 25on the surface of the hook 17 on the opposed surface of the knife blade36 instead, with attendant necessary structural changes.

A crank 39 having a crankpin 40 is connected to the bottom of the shaft31 of the knife carrier 30. A bore 41 is formed in the intermediateportion of the knife bracket 27 with its outlet end opening in proximityto the crankpin 40 of the crank 39. A piston 42 is slidably connected inthe outlet end of the bore 41 for coaction with the crankshaft 40 of thecrank 39. A tube or conduit 43 is connected to the inlet end of the bore41 and to a source of air under pressure.

In operation, air under pressure is introduced between the opposedsurfaces of the hook 17 and the knife blade 36 through the opening 25 inthe surface of the hook 17. Simultaneously, the surface of the knifeblade 36 opposite from the lug 37 is biased against the opposed surfaceof the hook 17 by means of the pressure of the piston 42 against thecrankshaft 40 of the crank 39.

After the loop seizing blade 20 through the oscillation of the hookshaft 13 has seized a loop of yarn, the knife blade 36 is oscillated bythe knife shaft 29 to cut the end of the loop of yarn by the scissorlikeaction of the cutting edge 21 of the loop-seizing blade 20 and thecutting edge 38 of the knife blade 36.

Thus, the introduction of air under pressure between the opposedsurfaces of the hook 17 and the knife blade 36 not only reduces thegeneration of heat caused by friction by interposing a cushion of airbetween the opposed surfaces of the book 17 and the knife blade 36 butfurther dissipates heat through the circulation of air. Instead ofheating up at high speeds, tests have indicated that the knife blade 36actually runs cooler than the ambient air. In addition, the air will notsoil the pile yarn as would be the case with oil and all similarlubricants, and the circulation of air prevents the accumulation of lintabout the book 17 and the knife blade 36. The use of a pneumatic piston42 in opposition to the force existed by the introduction of air underpressure between the opposed surfaces of the hook 17 and the knife blade36 makes it possible to adjust the characteristics of the cushion of airbetween the opposed surfaces of the hook 17 and the knife blade 36 bycoordinating the pressure of the air to the piston 42 with the pressureof the air introduced between the opposed surfaces of the hook 17 andthe knife blade 36,

Although the invention has been described in its preferred form with acertain degree of particularity, it is form has been made by way ofexample and that numerous changes in the details of construction and thecombination and arrangement of parts may be resorted towithout departingfrom the spirit and the scope of the invention.

What is claimed is:

1. In a tufting machine, a hook including a loop-seizing blade having acutting edge along its lower edge, -a knife blade having a cutting edgealong its upper edge, means for effecting relative motion between saidhook and said knife blade, said knife blade having one surface disposedin abutment with one surface of said hook for cooperation of the cuttingedge of said knife blade with the cutting edge of said hook duringrelative movement of said hook and said knife blade to cut a loop ofyarn on the loopseizing blade of said hook to produce cut pile, meansfor biasing said one surface of said knife blade against said onesurface of said hook, and means for introducing air under pressurebetween said opposed surfaces of said hook and said knife blade forreducing friction between said opposed surfaces of said hook and saidknife blade.

2. In a tufting machine, an osci-llatable hook including a loop-seizingblade having a cutting edge along its lower edge, an oscillatable knifeblade having a cutting edge along its upper surface, said knife bladehaving one surface disposed in abutment with one surface of said hookfor cooperation of the cutting edge of said knife blade with the cuttingedge of said hook during coordinated oscillation of said hook and saidknife blade to cut a loop of yarn on the loop-seizing blade of said hookto produce cut pile, pneumatic means for biasing said one surface ofsaid knife blade against said one surface of said hook, and means forintroducing air under pressure between said opposed surfaces of saidhook and said knife blade for reducing friction between said opposedsurfaces of said hook and said knife blade.

3. In a tufting machine, an oscillatable hook including a loop-seizingblade having a cutting edge along its lower edge, an oscillatable knifeblade having a cutting edge along its upper edge, said knife bladehaving one surface disposed in abutment with one surface of said hookfor cooperation of the cutting edge of said knife blade with the cuttingedge of said hook during coordinated oscillation of said hook and saidknife blade to cut a loop of yarn on the loop-seizing blade of said hookto produce cut pile, level means connected to said knife blade,pneumatic means disposed for coaction with said lever means for biasingsaid one surface of said knife blade against said one surface of saidhook, and means for introducing air under pressure between said opposedsurfaces of said hook and said knife blade for reducing friction betweensaid opposed surfaces of said hook and said knife blade.

References Cited by the Examiner UNITED STATES PATENTS 2,330,615 9/1943Parker 112-79 2,400,741 5/ 1946 Christensen 112218 FOREIGN PATENTS871,991 3/ 1953 Germany.

JORDAN FRANKLIN, Primary Examiner.

1. IN A TUFTING MACHINE, A HOOK INCLUDING A LOOP-SEIZING BLADE HAVING ACUTTING EDGE ALONG ITS LOWER EDGE, A KNIFE BLADE HAVING A CUTTING EDGEALONG ITS UPPER EDGE, MEANS FOR EFFECTING RELATIVE MOTION BETWEEN SAIDHOOK AND SAID KNIFE BLADE, SAID KNIFE BLADE HAVING ONE SURFACE DISPOSEDIN ABUTMENT WITH ONE SURFACE OF SAID HOOK FOR COOPERATION OF THE CUTTINGEDGE OF SAID KNIFE BLADE WITH THE CUTTING EDGE OF SAID HOOK DURINGRELATIVE MOVEMENT OF SAID HOOK AND SAID KNIFE BLADE TO CUT A LOOP OFYARN ON THE LOOPSEIZING BLADE OF SAID HOOK TO PRODUCE CUT PILE, MEANSFOR BIASING SAID ONE SURFACE OF SAID KNIFE BLADE AGAINST SAID ONESURFACE OF SAID HOOK, AND MEANS FOR INTRODUCING AIR UNDER PRESSUREBETWEEN SAID OPPOSED SURFACES OF SAID HOOK AND SAID KNIFE BLADE FORREDUCING FRICTION BETWEEN SAID HOOK OPPOSED SURFACES OF SAID HOOK ANDSAID KNIFE BLADE.